a flip-flop or latch is a circuit that has two stable states and can be used to store state information.

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Continuity LED Flip

I have a dual throw momentary switch. In the closed position (see below) it shows constant continuity thru an LED which I would also like to use as a counter. Or really an indicator that the switch ...
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25 views

T-type Flip-Flops with state-dependent switching times

A simple "On-Off" push-button circuit is easily implemented with a D-type flipflop. However, I need my flipflop to turn ON when the push-button is pressed and OFF when the push-button is pressed and ...
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1answer
39 views

Is it normal that a clock divider made with ring johnson counter has a momentary rising when the period changes?

I have made a clk divider using a ring johnson counter with D flip flop in VHDL. The point is that the signal output makes a momentary and unexpected rise during a change of period. As you can see in ...
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46 views

Shift registers, flip-flop, Multiplexer & Demultiplexer with microcontrollers utility

While i read alot about the popular 74HC595 shift register and its use for multiplexing i can't find anything about the following chips: MC14053B Triple 2−Channel Analog Multiplexer/Demultiplexer ...
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40 views

Capturing x86 register value changes in hardware i.e. at circuit level

I need to find a way of observing (on another 'monitor' machine) changes to registers critical to the address translation process on x86 platforms - including IDTR, GDTR, CR3, etc. This monitoring ...
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60 views

shift registers/d flip-flop memory states

I know D flip-flops retain a certain logic level(memory) but when they output(i.e. shift) this retain memory do they loose it? for example: lets say I have 3 d flip-flops connected as a serial shift ...
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133 views

Toggle state between two circuits with two momentary switches

I have two circuits each with their own 1.5v power supply. I would like to toggle state between the two circuits with a switch, so that hitting a momentary switch turns the light off on one and turns ...
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66 views

Help with On/Off Flip Flop Switch

I'm still fairly new to electronics and have been teaching myself as a hobby. Currently I'm working on a project that detects a red laser beam, and once detected will turn AC lights OFF if they're ...
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2answers
46 views

J-K Flip Flop and Toggle

While investigating the design of J-K Flip Flop, I cannot get my head around how toggle work. I know it only toggle as the clock goes from 0 to 1. Here's my false understanding of how the toggle ...
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2answers
55 views

Syncronization Flip-flops

I've a doubt about clock domains and synchronization FF. I'm working on a FPGA and I've two clock domains. In the firs clock domain there is a clock frequency of 125 MHz, in the second the frequency ...
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1answer
50 views

problem on logic 0 at 4027 ic

I have a circuit to generate simple sound with astable multivibrator and enable/disable it with j-k flip flop with reset pin, something like this pic: i have a problem with logic 0, when it occurs ...
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32 views

Problem while linking flip flop D in VHDL

I have defined a single Dflipflop with the following code (and I suppose It works): ...
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44 views

State diagram for JK-flip-flop

I'm trying to create a simple state-diagram for a JK flip-flop, and this is what I've come up with. I've seen other variants of this diagram, but to me this seems like a correct one if you look at ...
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1answer
40 views

Shift register on sync RS flip-flop

I am trying to build serial-in shift register (non cycled) based on synchronous RS flip-flop, but i'v got a problem with synchronization. My clock generator was configured to long on period and short ...
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1answer
67 views

Implementing a FSM using JK flip flops in VHDL

This is yet another semester project I'm stuck on. I need to implement a state machine starting from the following diagram: What I've managed to do so far is write this state table, although I'm ...
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1answer
32 views

drawing flipflop after statement table and kmap simplification

I try to make counter using flipflop. 15-0-1-2-8-7-5-13-6-9-15 synchronous counter using D flipflop Here is table: Kmap simplifications: After the steps, I don't know (what I do) how to draw ...
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3answers
193 views

Using just one output of a J-K flip-flop

If I am using a J-K flip-flop, but only need one of the outputs, what should I do with the other? Leave it disconnected, or tie it high/low (via a resistor?) Why?
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98 views

Designing a State Machine

Question: Design a state machine that would output the sequence 0 1 7 1 and then 1 7 1 1 7 1 and so on. A reset will make the machine go to the which outputs 0? What I've managed to do so far: Since ...
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3answers
82 views

Component selection - difference between 4027 and 4027N flip flops

I am building a simple circuit that will use a J-K flip flop to enable me to use a momentary switch as a toggle. The circuit diagram states that a 4027N should be used. My local supplier has a ...
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2answers
71 views

How to design, build and test synchronous sequential circuits using D-Flip Flops?

I want to design, build and test synchronous sequential circuits by using D-Flip Flops. I know how to analyze state diagrams but I don't now how to obtain a state diagram using just outputs. P.S. : ...
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2answers
36 views

SR Latch/Racing?

Following truth table resulted from the circuit below. SR(NOR) latch is used. I have tried several times to trace through the circuit to see how truth table values are produced but its not working. ...
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1answer
45 views

Saving the state of the LED on illuminated momentary button

I have three illuminated momentary buttons with a separate anode and cathode for the led. (source of image) I want a circuit that illuminates the LED of the button that was most recently ...
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0answers
31 views

ltspice with large transistor array takes long time to solve

I have been working on a project to create several of the same T Flip-Flops with different components in LTSpice. The first uses the built in dflop object from LTSpice and the xor. I then moved to ...
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2answers
95 views

Resetting a counter when it reaches 6, without logic gates

I have a 3 bit ripple counter (using t flip flops) and I want the counter to reset to one when it reaches 7 i.e. the counter counts from 1 to 6. My idea was that I could hook the three outputs from ...
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38 views

how to Make Mealy machine output synchronous?

I have seen in slide below (and of course with some thought ) that the output of a Mealy machine is not synchronous . (you can find the whole slide in here). to make it synchronous the slide note ...
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1answer
77 views

JK Flip Flop Circuit Output

I have a group project that requires us to use three flip flops with the following requirements. If x = 0 and y = 0, the counter remains the same. If x = 0 and y = 1, the circuit through the state ...
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110 views

Who triggers transistors to become H/L?

Admittedly that's quite a beginner question: When I learned that transistors work like relays and produce the digital values 0 and 1 what I always asked myself was: they have to be triggered by ...
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1answer
99 views

How to design a Design a 64 x 8 memory using two 16 x 4 RAM chip? [closed]

Can someone suggest how I would start this project? I want to design a Design a 32 x 4 memory using two 16 x 4 RAM chip.
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2answers
104 views

VHDL JK Flip-Flop with logic gates

I am trying to make a JK flip-flop in ActiveHDL environment. I want to make it with logic gates. It should look like this: This is my code: ...
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1answer
46 views

How can the flip flop neglect clear when given output is given as feedback?

Here is how the circuet looks. Initally the output the D flip flop is HIGH, when the there is HIGH to LOW input across the multivirator, it create a pulse of 200ms, which is connected to the Clear ...
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2answers
39 views

What does splitter do in logisim?

I have just started learning logisim, so i have a very simple question. My question is what does splitter do. Whats its function and how can we actually implement it(like on breadboard or trainer ...
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2answers
317 views

How to create a frequency doubler circuit using only flipflops/ Digital elements?

First things first, is it even possible to scale up the frequency using only digital elements, atleast approximately? Though a frequency divider circuit can be designed very easily with flipflops. In ...
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2answers
119 views

JK Flip Flop Counter

I am designing a counter circuit that will perform the following function: A sequential circuit with three flip-flips A, B and C and two inputs X and Y. If X=0 and Y=0, the counter remains in the ...
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1answer
73 views

Significance of negative setup and hold time

What do you mean by negative setup and hold time i.e what happens if hold time is negative or setup time is negative. Does -ve setup or hold have any advantage ?
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1answer
113 views

Rising edge pulse detector from logic gates

The circuits I describe are entirely made of 7400 series logic gates (7402, 7404 and 7408 ic). I'm trying to build a rising (positive) edge pulse detector using logic gates. The following circuit ...
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4answers
123 views

is flip flop a synchronous or an asynchronous sequential circuit?

i have read in my text book that : " A flip-flop is the simplest synchronous sequential circuit. " but it is not convincing at all since we cannot analyze or build a flip flop like a synchronous ...
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1answer
34 views

SR Flip-flop builded from 2 SR-Latch

I just study about flip-flop in my class and this is the picture from the slide my teacher used that explain the construction of SR Flip-flop However, I find something was wrong with this figure. ...
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1answer
57 views

Using a block diagram for the RS flipflop, add appropriate gates for a D-flipflop

I have been given the problem "Using a block diagram for the RS flipflop, add appropriate gates for a D-flipflop". Now, I can create the gate diagram for both RS flipflop and D flipflop ...
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3answers
211 views

D-Flip Flop Frequency Divider - Simulates but doesn't work on protoboard

I'm having a problem that is probably trivial, but I can't seem to make any progress. Just a disclaimer, I'm an analog EE and digital design isn't my strong suite. That being said, I'm trying to build ...
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2answers
68 views

How to convert this NOT/AND/OR counter to an all NAND counter?

Sequence: 000,010,111,001,100... Have to build it using a JK Flip Flop for Q0 and 2 D flip flops for Q1 and Q2 and all NAND gates. Basically I have no problem building this counter with just the ...
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3answers
982 views

SR Flip Flop: NOR or NAND?

I started studying flip flips recently and I am stuck at this point: At some video tutorials, people explain the SR Flip Flop like this: So they use NAND gates, producing a transition table like ...
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3answers
33 views

number of bits of information for n stable states?

my text book says "An element with N stable states conveys log2N bits of information" i don't understand it since i expect if we have n stable states we would have n/2 bits since one of them is ...
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0answers
141 views

Design serial adder for 16 bit register using on full FA

I wrote a serial bit adder for a 15 bit width shift register and a full adder (positive edge trigger, asynchronous reset) I don't know where the error in this code is. This is the code: ...
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1answer
95 views

Can I use an AND gate before a clock input?

Can I use an AND gate with a clock input? For example, in the picture below, I have a positive-edge D flip-flop. I'm using an AND gate with the Select_chip input and the Clock input but I'm not sure ...
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1answer
151 views

Constructing a Sequential Circuit with two D Flip Flops

A sequential circuit with two D flip flops (A and B), two inputs (x and y), and one output (z) is specified by the following next-state and output equations: A(t+1) = xy' + xB B(t+1) = xA + xB' z = ...
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2answers
82 views

1/6 Clock Frequency Divider

How would I design a circuit made of rising edge triggered flip flops and inverters to make its output 1/6 of the clock frequency. Cheers
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3answers
55 views

How could I set up a circuit that keeps track of strikes in a baseball game using D flip flops in Multisim?

What I want is two LED lights and a push button. When the push button is pressed the first time, the first light lights up. When it's pressed a second time, the second light lights up. When it's ...
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3answers
69 views

Why is it when I set up a Johnson counter, the number sequence rotates fine, but I can't get a ring counter right (explanation below)?

With a Johnson counter, I hook up every flip flop's Q output to the following flip flop's D input, for D flip flops. And then the final Q' output is hooked into the first flip flop's D input. When I ...
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1answer
94 views

Verilog inital value for flip flop

I am trying to write verilog code that will set the initial value of the output of a positive-edge triggered flip-flop to 0. The behaviour of the flip-flop circuit is exactly what I want AFTER the ...
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3answers
189 views

Reduced clock speed with flip flop

My question is if there is a way to reduce a clock to two thirds of its speed using flip flops because i know a flip flop cuts its speed in half.